| Summary: | The term "axona migration" may be given two meanings: a narrow and a broad one. The term in its narrow sense refers only to the hypothesis that a certain material present in the axon would migrate in a peripheral direction, a good example of this concept is provided by the neurosecretion theory in which neurosecretory granules are believed to migrate distally along the axon. The broad meaning, as outlined in Weiss's concept implies proximodistal movement of the axon as a whole and therefore correspnds to a "continuous growth of the axon." According to Weiss and Hiscoe (1948), this theory is summarized as follow: "Growth, in the sense of production of new protoplasm, occurs solely at the base of the fiber in the nucleated part of the cell body. the column of axoplasm is maintained in constant proximodistal motion. Growth and centrifugal convection of axoplasm are not confined to the period of active elongation and enlarement, but continue in the mature fiber which has reached a stationary condition. The perpetual growth of the neurone presumably serves to replace kutabolized protoplasmic systems, especially proteins, which cannot be synthesized in the peripheral cytoplasm." [...]
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